In the hinterland in which improv can sound like contemporary classical music, spontaneity like composition and postbop like 21st-century Bach, the pairing of Swiss pianist Sylvie Courvoisier and her violinist husband Mark Feldman represent one of the most creative combinations. Feldman is a former Nashville country fiddler with a classical player's tone and precision, Courvoisier is an improvising pianist who has worked with guitarist Fred Frith, but whose classical training often surfaces. This quartet session is completed by the young bassist Thomas Morgan (recently heard in the UK with Craig Taborn) and drummer Gerry Hemingway. This absorbing session's free-improv associations are conspicuous in episodes of drifting violin figures against trickling piano musings, and abrasive chords over stabbed low-end notes and percussion furores, yet the overall impression is of audaciously reworked lyricism, and an accessible narrative shapeliness. The dancing melody of the opening Messianesque is typical of Courvoisier and Feldman's long-evolved empathy, and the suite-like Five Senses of Keen is a miniature masterpiece of solemn high-register violin figures and subtly harmonised chords, like distant Gregorian chants, interspersed with Courvoisier's punchier percussive departures. The pianist even sounds eerily like Thelonious Monk on the tramping Coastlines.